Bottoming cycle power system

ABSTRACT

A bottoming cycle power system includes a turbine-generator having a turbo-expander and turbo-compressor disposed on a turbo-crankshaft. The turbo-expander is operable to rotate the turbo-crankshaft as a flow of exhaust gas from a combustion process passes through the turbo-expander. The turbo-compressor is operable to compress the flow of exhaust gas after it passes through the turbo-expander. An exhaust-gas heat exchanger having first and second flow paths. The first flow path is operable to receive the flow of exhaust gas from the turbo-expander prior to the exhaust gas being compressed by the turbo-compressor. The second flow path is operable to receive the flow of exhaust gas from the turb-compressor. A processing system is operable to cool the flow of exhaust gas after the exhaust gas has passed through the first flow path and prior to the exhaust gas being compressed by the turbo-compressor.

TECHNICAL FIELD

The present disclosure relates to systems for delivering power. Morespecifically, the disclosure relates to a bottoming cycle power systemfor delivering power, such as mechanical or electrical power.

BACKGROUND

One of the most challenging aspects of today's energy technologies is toeffectively convert waste heat from a combustion process into useablepower. Such power can be in the form of electrical or mechanical powerfor use in stationary and/or mobile applications.

Methods of converting waste heat into useful forms of energy arecommonly referred to as bottoming cycles. Systems that utilize abottoming cycle to provide power are referred to herein as bottomingcycle power systems.

Systems that utilize a fuel combustion process in an internal combustionengine (such as a piston engine or a turbine engine) as the motive forceto drive a crankshaft for providing power are referred to herein asprimary power systems. In most primary power systems the efficiency ofthe system ranges from below 30% to a high of almost 50%. This meansthat the majority of energy contained in the fuel is lost in the form ofheat to the atmosphere through either the cooling circuit or exhaust ofthe internal combustion engine.

However, the waste energy contained in exhaust gas from the internalcombustion engine of a primary power system may be utilized as theenergy input for a bottoming cycle power system. If enough useful workcan be recovered from such a bottoming cycle power system, the bottomingcycle power system could then be used to supplement the output of theprimary power system for a more efficient overall system output.

One type of bottoming cycle is known as an inverted Brayton cycle. Theinverted Brayton cycle typically includes an expansion turbine (orturbo-expander) that receives a flow of exhaust gas from a combustionprocess of an internal combustion engine. The exhaust gas carries asignificant amount of heat energy. However the flow of exhaust gas istypically only at, or slightly above, atmospheric pressure. For example,the exhaust gas may exit the internal combustion engine at about900-1100 degrees Fahrenheit (F), but at only a few pounds per squareinch (psi) above atmospheric pressure. This makes recovering useful workdifficult.

In the inverted Brayton cycle, the exhaust gas flows through aturbo-expander where it typically exits the turbo-expander at belowatmospheric pressures (or vacuum pressures). The vacuum pressures arecaused by a compression turbine (or turbo-compressor), which is thefinal step in the inverted Brayton cycle. That is, the exhaust gasenters the turbo-compressor where it may be pumped back to atmosphericpressure. The amount of energy recovered from an inverted Brayton cycleis the energy produced by the turbo-expander minus the energy consumedby the turbo-compressor. Therefore, the less work needed by theturbo-compressor to compress the expanded volume of exhaust gas, thegreater the net-work produced from the inverted Brayton cycle.

Various prior art cooling systems can be utilized to reduce the specificvolume of exhaust gas prior to entering the turbo-compressor in aninverted Brayton cycle and, therefore, reduce the amount of workrequired by the turbo-compressor to compress the exhaust gas.Problematically however, these cooling systems consume a significantamount of energy due to pumps and/or other energy consuming devicesneeded to circulate coolants through the cooling system.

Moreover, the more the exhaust gas is cooled in order to produce as muchnet-work from the inverted Brayton cycle (or other bottoming cycles) aspossible, the more the density of the cooled exhaust gas will increase.Problematically, if the exhaust gas is cooled to ambient or near ambienttemperatures, the exhaust gas will become too dense to flow up therequired stack of the internal combustion engine. In that case, theexhaust gas must be re-heated as it exits the turbo-compressor, whichmay significantly reduce the amount of net-work that the invertedBrayton-cycle can provide.

Further, the exhaust gas of an internal combustion engine contains asignificant amounts of water vapor and carbon dioxide as naturallyoccurring by-products of the combustion process. Problematically, thewater vapor has a relatively high specific volume and mass, which causesan unwanted burden on the compression work of the compressor in theinverted Brayton cycle. Also problematically, prior art carbon dioxidecapture systems generally consume a significant amount of energy toremove the carbon dioxide from the exhaust gas, which would also cause aburden on the efficiency of the internal combustion engine.

Accordingly, there is a need for a bottoming cycle power system, such asan inverted Brayton bottoming cycle power system, wherein the specificvolume of flow of exhaust gas is significantly and efficiently reducedafter exiting the turbo-expander and prior to entering theturbo-compressor. More specifically, there is a need to reduce the workrequired of the turbo-compressor in a bottoming cycle power system toincrease the overall efficiency of that bottoming cycle power system.

Further there is a need to efficiently decrease the volume and mass ofwater vapor in a flow of exhaust gas prior to entering theturbo-compressor of a bottoming cycle power system. Additionally, thereis a need to efficiently re-heat exhaust gas that has been cooled toambient or near ambient temperatures, in order to enable the exhaust gasto flow up an internal combustion engine's stack with little drain onthe net-work of the associated bottoming cycle power system.Additionally, there is a need to reduce the energy required in anycarbon dioxide capture system used to remove the carbon dioxide fromexhaust gas and, therefore, help to maintain the efficiency of theinternal combustion engine associated with the bottoming cycle powersystem.

BRIEF DESCRIPTION

The present disclosure offers advantages and alternatives over the priorart by providing a bottoming cycle power system for receiving a flow ofexhaust gas from a combustion process. The bottoming cycle power systemincludes an exhaust gas heat exchanger that has a first and a secondflow path. The first flow path receives hot exhaust gas after it hasexited the turbo-expander and prior to entering the turbo-compressor ofthe bottoming cycle power system. The second flow path receives cooledexhaust gas after it has exited the turbo-compressor. The cooled exhaustgas provides a first stage of cooling of the hot exhaust gas as itpasses through the exhaust gas heat exchanger. An exhaust gas processingsystem is disposed between the exhaust gas heat exchanger and theturbo-compressor to provide at least a second stage of cooling of theexhaust gas prior to entering the turbo-compressor.

A bottoming cycle power system in accordance with one or more aspects ofthe present disclosure includes a turbine-generator. Theturbine-generator includes a turbo-expander and turbo-compressordisposed on a turbo-crankshaft. The turbo-expander is operable to rotatethe turbo-crankshaft as a flow of exhaust gas from a combustion processpasses through the turbo-expander. The turbo-compressor is operable tocompress the flow of exhaust gas after the exhaust gas passes throughthe turbo-expander. An exhaust gas heat exchanger includes first andsecond flow paths operable to exchange heat therebetween. The first flowpath is operable to receive the flow of exhaust gas from theturbo-expander prior to the exhaust gas being compressed by theturbo-compressor. The second flow path is operable to receive the flowof exhaust gas from the turbo-compressor after the exhaust gas has beencompressed by the turbo-compressor. An exhaust gas processing system isoperable to receive and cool the flow of exhaust gas after the exhaustgas has passed through the first flow path of the exhaust gas heatexchanger and prior to the exhaust gas being compressed by theturbo-compressor.

A combined power system in accordance with one or more aspects of thepresent disclosure includes a primary power system and a bottoming cyclepower system. The primary power system includes an internal combustionengine having a rotatable crankshaft. The engine is operable to use fuelin a combustion process to deliver primary power to the enginecrankshaft. The combustion process produces a flow of exhaust gas. Thebottoming cycle power system includes a turbine-generator. Theturbine-generator includes a turbo-expander and turbo-compressordisposed on a turbo-crankshaft. The turbo-expander is operable to rotatethe turbo-crankshaft as the flow of exhaust gas from the combustionprocess passes through the turbo-expander. The turbo-compressor isoperable to compress the flow of exhaust gas after the exhaust gaspasses through the turbo-expander. An exhaust gas heat exchangerincludes first and second flow paths operable to exchange heattherebetween. The first flow path is operable to receive the flow ofexhaust gas from the turbo-expander prior to the exhaust gas beingcompressed by the turbo-compressor. The second flow path is operable toreceive the flow of exhaust gas from the turbo-compressor after theexhaust gas has been compressed by the turbo-compressor. An exhaust gasprocessing system is operable to receive and cool the flow of exhaustgas after the exhaust gas has passed through the first flow path of theexhaust gas heat exchanger and prior to the exhaust gas being compressedby the turbo-compressor.

A carbon dioxide capture system in accordance with one or more aspectsof the present disclosure includes a first capture tank, a secondcapture tank, a carbon dioxide compressor and a compressor coolant loop.Each capture tank contains carbon dioxide absorbent material operable toabsorb carbon dioxide from a flow of exhaust gas. The first and secondcapture tanks each include an exhaust gas inlet port, an exhaust gasoutlet port and a carbon dioxide outlet port. The exhaust gas inlet portof each capture tank is selectively connectable to the flow of exhaustgas prior to the exhaust gas passing through the carbon dioxideabsorbent material. The exhaust gas outlet port of each capture tank isselectively connectable to the flow of exhaust gas after the flow ofexhaust gas has passed through carbon dioxide absorbent material. Thecarbon dioxide compressor is selectively connectable to the carbondioxide outlet port of either the first or second capture tank. Thecarbon dioxide compressor is operable to pump carbon dioxide out of thecarbon dioxide outlet port that the carbon dioxide compressor isconnected to. The compressor coolant loop is selectively connectablebetween the carbon dioxide compressor and the first capture tank orbetween the carbon dioxide compressor and the second capture tank. Thecompressor coolant loop is operable to flow a compressor coolant fluidto remove heat of compression from the compressor and to transfer theheat of compression to the first or second capture tank. The heat ofcompression is operable to release a portion of the carbon dioxideabsorbed by the carbon dioxide absorbent material in the first or secondcapture tank.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail below (provided suchconcepts are not mutually inconsistent) are contemplated as being partof the inventive subject matter disclosed herein and may be used toachieve the benefits and advantages described herein.

DRAWINGS

The disclosure will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a schematic of an example of a combined power system having aprimary power system and a bottoming cycle power system, wherein thebottoming cycle power system includes a turbine generator, an exhaustgas heat exchanger and an exhaust gas processing system, in accordancewith the present disclosure;

FIG. 2 is a schematic of an example of the combined power system of FIG.1 further including a carbon dioxide capture system, in accordance withthe present disclosure;

FIG. 3 is schematic of an example of the combined power system of FIG.2, with a detailed view of the exhaust gas processing system and thecarbon dioxide capture system, in accordance with the presentdisclosure;

FIG. 4 is a schematic of an example of a detailed view of an absorptionchiller heat exchanger and associated absorption chiller that may beutilized in the exhaust gas processing system of FIG. 3, in accordancewith the present disclosure;

FIG. 5 is a schematic of an example of a detailed view of a coolingtower heat exchanger and associated cooling tower that may be utilizedin the exhaust gas processing system of FIG. 3, in accordance with thepresent disclosure; and

FIG. 6 is a schematic of an example of an enlarged view a carbon dioxidecapture system that may be utilized in the combined power system of FIG.3, in accordance with the present disclosure.

DETAILED DESCRIPTION

Certain examples will now be described to provide an overallunderstanding of the principles of the structure, function, manufacture,and use of the methods, systems, and devices disclosed herein. One ormore examples are illustrated in the accompanying drawings. Thoseskilled in the art will understand that the methods, systems, anddevices specifically described herein and illustrated in theaccompanying drawings are non-limiting examples and that the scope ofthe present disclosure is defined solely by the claims. The featuresillustrated or described in connection with one example maybe combinedwith the features of other examples. Such modifications and variationsare intended to be included within the scope of the present disclosure.

The terms “significantly”, “substantially”, “approximately”, “about”,“relatively,” or other such similar terms that may be used throughoutthis disclosure, including the claims, are used to describe and accountfor small fluctuations, such as due to variations in processing from areference or parameter. Such small fluctuations include a zerofluctuation from the reference or parameter as well. For example, theycan refer to less than or equal to ±10%, such as less than or equal to±5%, such as less than or equal to ±2%, such as less than or equal to±1%, such as less than or equal to ±0.5%, such as less than or equal to±0.2%, such as less than or equal to ±0.1%, such as less than or equalto ±0.05%.

Referring to FIG. 1, a schematic is depicted of an example of a combinedpower system 100 having a primary power system 102 and a bottoming cyclepower system 104, wherein the bottoming cycle power system 104 includesa turbine generator 120, an exhaust gas heat exchanger 106 and anexhaust gas processing system 108, in accordance with the presentdisclosure. In this example, the bottoming cycle power system 104 is aninverted Brayton bottoming cycle power system 104.

In this specific example, the combined power system 100, primary powersystem 102 and bottoming cycle power system 104 are configured togenerate electrical power to, for example, a grid (i.e., an interconnectnetwork for delivering electricity from producers to consumers).However, it is within the scope of the present disclosure, that thepower systems 100, 102 and 104 could be used to provide mechanical poweras well.

Moreover, such power systems of the present disclosure may be used inboth stationary applications and mobile applications. Examples of suchstationary applications include electric generator systems fordelivering electric power to a grid, electric generator systems fordelivering electric power to a building, mechanical power systems fordelivering mechanical power for an industrial manufacturing process orthe like. Examples of such mobile applications include mechanical powersystems for delivering mechanical power to a motor vehicle, electricalpower systems for delivering electrical power to an electric vehicle orthe like.

The primary power system 102 includes an internal combustion engine 110having an engine crankshaft 112 that is operatively connected to aprimary electric generator 114. The internal combustion engine 110 mayinclude a turbine engine, a piston engine or similar. The engine 110utilizes fuel in a combustion process as the motive force that rotatesthe engine crankshaft 112 and the primary electric generator 114 togenerate a first electrical output 115. Additionally, the combustionprocess produces a flow of exhaust gas 116, which may be routed to thebottoming cycle power system 104. The flow of exhaust gas from thecombustion process of the internal combustion engine 110 may be at, ornear, atmospheric pressure and may have a temperature in the range of850 to 950 degrees Fahrenheit (F).

Though in this example, the combustion process and associated the flowof exhaust gas 116 is utilized within a primary power system 102, otherdevices and/or systems may utilize a combustion process to produceexhaust gas 116. For example, the exhaust gas may be produced from afurnace system, or from burning natural gas at an oil well site or thelike.

The bottoming cycle power system 106 includes a turbine generator 120.The turbine generator 120 includes a turbo-expander 122 andturbo-compressor 124 disposed on a turbo-crankshaft 126. Theturbo-expander 122 is operable to receive and expand the flow of exhaustgas 116 from the combustion process of the internal combustion engine110. The turbo-expander 122 is operable to rotate the turbo-crankshaft126 as the exhaust gas 116 passes through the turbo-expander 122. Theturbo-expander 122 expands the exhaust gas 116 to extract energy fromthe exhaust gas 116 and convert the energy to work on the crankshaft126. Because the exhaust gas 116 is expanded as it passes through theturbo-expander 122, the exhaust gas 116 will be under a vacuum as itexits the turbo-expander 122, for example, at a vacuum pressure ofperhaps 0.2 atmospheres. Additionally, the exhaust gas 116 will cool asit performs work on the crankshaft, for example within a range of500-700 degrees F.

The turbo-compressor 124 (typically a turbine compressor or similar) isoperatively connected to the flow of exhaust gas 116. More specifically,as the turbo-compressor 124 is rotated by the turbo-crankshaft 126, theturbo-compressor is operable to compress the flow of exhaust gas 116after the exhaust gas passes through the turbo-expander 122, the exhaustgas heat exchanger 106 and the exhaust gas processing system 108.

Additionally, the turbo-compressor 124 pulls a vacuum on the output sideof the turbo-expander 122 (for example a vacuum of about 0.2atmospheres) to increase a pressure difference across the turbo-expander122. The increased pressure difference enhances the expansion of theflow of exhaust gas 116 through the turbo-expander 122 in order toconvert as much energy in the exhaust gas 116 into usable work on theturbo-crankshaft 126.

A bottoming cycle generator 128 is also disposed on the turbo-crankshaft126. The bottoming cycle generator 128 is operable to generateelectrical power when the turbo-crankshaft 126 is rotated by theturbo-expander 122. In other words, the bottoming cycle generator 128generates a second electrical output 118 that may be used to supplementthe first electrical output 115 of the primary power system 102.

The exhaust gas 116 flows from the turbo-expander 122 into the exhaustgas heat exchanger 106. The exhaust gas heat exchanger 106 includes afirst flow path 130 and a second flow path 132 operable to exchange heattherebetween. More specifically, the first flow path 130 is operable totransfer heat into the second flow path 132. The first flow path 130 isoperable to receive the flow of exhaust gas 116 from the turbo-expander122 prior to the exhaust gas 116 being compressed by theturbo-compressor 124. The second flow path 132 is operable to receivethe flow of exhaust gas 116 from the turbo-compressor 124 after theexhaust gas 116 has been compressed by the turbo-compressor 124.

As will be explained in greater detail herein, the hot exhaust gas 116from the turbo-expander 122 (for example at about a temperature of500-700 degrees F.), that flows through the first flow path 130 of theexhaust gas heat exchanger 106, is cooled by the much cooler exhaust gas116 (for example at about a temperature range of 60-80 degrees F.) fromthe turbo-compressor 124, that flows through the second flow path 132 ofthe exhaust gas heat exchanger 106.

Advantageously, the cooled exhaust gas 116 from the turbo-compressor 124provides a first stage of cooling for the hotter exhaust gas 116 fromthe turbo-expander 122. For example, the exhaust gas 116 may be cooleddown to about a range of 200-300 degrees F. as it exits the first path130 of the exhaust gas heat exchanger 106.

Also, advantageously, the hotter exhaust gas 116 from the turbo-expander122 reheats the cooler exhaust gas 116 from the turbo-compressor 124 totemperatures that enable the exhaust gas 116 to flow readily up a stack164 (see FIG. 3) of the combined power system 100. For example, theexhaust gas 116 exiting the second path 132 of the gas heat exchanger106 may be within a range of about 250-350 degrees F.

The stack 164, as used herein, will refer to the extended exhaust pipingsystem designed to route exhaust gas away from the source of thecombustion process (in this example, the source of the combustionprocess is the internal combustion engine 110). In this example, thestack 164 of the combined power system 100 is designed to route the flowof exhaust gas 116 away from the combined power system 100 after theexhaust gas exits the second path 132 of the exhaust gas heat exchanger106 (see FIG. 3).

The stack 164 of the combined power system 100 is required to route theexhaust gas 116 away from the combined power system 100 and to maintainair quality in the proximity of the combined power system 100. The stack164, by regulation, may have a minimum height that may be as much as 1.5times the height of a building or container that houses the engine 110or more. If the exhaust gas 116 is too cool (for example, near or belowambient temperature), the exhaust gas 116 will be too dense to readilyflow to the top of the stack 164. As will be explained in greater detailherein, cooling the exhaust gas 116 to near ambient temperature beforeit enters the turbo-compressor 124 is advantageous for increasing thecompression ratio (and therefore efficiency) across the turbo-expander122. However, reheating the exhaust gas 116 to temperatures that aresignificantly higher than ambient temperature after the exhaust gas 116exits the turbo-compressor 124 is advantageous for routing the exhaustgas 116 up the stack 164. The exhaust gas heat exchanger 106 helps toperform both of these functions.

The exhaust gas processing system 108 is operable to receive and coolthe flow of exhaust gas 116 after the exhaust gas 116 has passed throughthe first flow path 130 of the exhaust gas heat exchanger 106 and priorto the exhaust gas 116 being compressed by the turbo-compressor 124. Theexhaust gas processing system 108 provides a second stage of cooling forthe exhaust gas 116 prior to the exhaust gas 116 entering theturbo-compressor 124.

Referring to FIG. 2, a schematic of an example is depicted of thecombined power system 100 of FIG. 1 further including a carbon dioxidecapture system 134, in accordance with the present disclosure. Thecarbon dioxide capture system 134 is operable to remove and capturecarbon dioxide 206 from the exhaust gas 116 after the exhaust gas 116exits the turbo-compressor 124 and prior to the exhaust gas 116 flowingthrough the second flow path 132 of the exhaust gas heat exchanger 106.As will be explained in greater detail herein, the carbon dioxidecapture system 134 is also operable to advantageously regenerate thecaptured carbon dioxide 206 using a heat of compression of a carbondioxide compressor 220 (see FIG. 6).

Referring to FIG. 3, a schematic is depicted of an example of thecombined power system 100 of FIG. 2, with a more detailed example of theexhaust gas processing system 108 and the carbon dioxide capture system134, in accordance with the present disclosure. The exhaust gasprocessing system 108 performs at least a second stage of cooling on theexhaust gas 116 after the exhaust gas 116 exits the exhaust gas heatexchanger 106. However, the exhaust gas processing system 108 mayperform other functions as well. For example, the exhaust gas processingsystem 108 may perform several stages of cooling and/or may remove waterfrom the flow of exhaust gas 116.

In the specific example depicted in FIG. 3, the exhaust gas processsystem 108 includes a cooling tower heat exchanger 136, an absorptionchiller heat exchanger 138 and a dehumidifier system 140 that processthe exhaust gas 116 as it passes through the exhaust gas processingsystem 108. The cooling tower heat exchanger 136 performs a second stageof cooling on the exhaust gas 116, the absorption chiller heat exchanger138 performs a third stage of cooling on the exhaust gas 116 and thedehumidifier system 140 removes water from the exhaust gas 116 prior tothe exhaust gas entering the turbo-compressor 124.

The cooling tower heat exchanger 136 is operable to receive the flow ofexhaust gas 116 from the exhaust gas heat exchanger 106. The coolingtower heat exchanger 136 is operable to cool the exhaust gas 116 with aflow of cooling tower coolant fluid 141 (see FIG. 5) that flows in acooling tower coolant loop 142 between a cooling tower 144 and thecooling tower heat exchanger 136. In this specific example, the coolingtower coolant fluid is water, but may also be other coolants, such asglycol or the like. The cooling tower heat exchanger 106, may, forexample, cool the exhaust gas down to a temperature range of about100-130 degrees F.

From the cooling tower heat exchanger 136, the exhaust gas 116 flows tothe absorption chiller heat exchanger 138. The absorption chiller heatexchanger 138 is operable to receive the flow of exhaust gas 116 fromthe exhaust gas heat exchanger 136 and to cool the exhaust gas 116 witha flow of absorption chiller coolant fluid (such as water, glycol or thelike) that flows in an absorption chiller coolant loop 146 between anabsorption chiller 148 and the absorption chiller heat exchanger 138.For example, the absorption chiller heat exchanger 136 may cool theexhaust gas 116 down to a range of about 35-45 degrees F.

A coolant pump 150 may be used to pump the absorption chiller coolantfluid around the absorption chiller coolant loop 148. An expansion tank152 may be used to provide room for thermal expansion of the absorptionchiller coolant fluid as it is circulated around the absorption chillercoolant loop 146.

The absorption chiller 148 may be powered by the heat energy from anengine coolant loop 154 of the internal combustion engine 110. Morespecifically, engine coolant fluid may be circulated in the enginecoolant loop 154, via a coolant pump 156, between a generator section166 (see FIG. 4) of the absorption chiller 148 and the engine 110.

Additionally, a water tower 158 may be used to remove heat energy fromthe absorption chiller 148. More specifically, a water tower 158 maycirculate a flow of water tower coolant fluid (such as water, glycol orthe like) in a water tower coolant loop 160 between the water tower 158and the absorption chiller 148 to remove heat from an evaporator section170 (see FIG. 4) and an absorption section 172 (see FIG. 4) of theabsorption chiller 148.

In the specific example illustrated in FIG. 3, the exhaust gas 116 flowsfrom the cooling tower heat exchanger 136 directly into the absorptionchiller heat exchanger 138. However, other examples of the exhaust gasprocessing system 108 are within the scope of this disclosure. Forexample, the exhaust gas 116 may flow into the absorption chiller heatexchanger 138 first and then into the cooling tower heat exchange 136.Alternatively, there may be only an absorption chiller heat exchanger138 or only a cooling tower heat exchanger 136 in the exhaust gasprocessing system 108.

Additionally, there may be other types of cooling systems utilized tocool the exhaust gas 116 in lieu of, or in place of, the cooling towerheat exchanger 136 and absorption chiller heat exchanger 138. Forexample, various types of vapor-compression refrigeration systems (notshown) may be utilized to cool the exhaust gas 116 in the exhaust gasprocessing system 108.

From the absorption chiller heat exchanger 138, the exhaust gas 116 mayoptionally flow through the dehumidifier system 140. The dehumidifiersystem 140 is operable to remove a substantial amount of water from theexhaust gas 116. The dehumidifier system may use various waterabsorption materials (for example lithium bromide, activated charcoal,calcium chloride, zeolites or other types of hygroscopic substances) toabsorb water 160 from the exhaust gas 116. The water 160 may be pumpedaway from the dehumidifier system 140 via water pump 162. Though thisparticular example of an exhaust gas processing system 108 includes adehumidifier system 140, it is within the scope of this disclosure thata dehumidifier system not be utilized in the exhaust gas processingsystem 108.

From the dehumidifier system 140, the exhaust gas 116 flows into theturbo-compressor 124. At this stage of exhaust gas flow 116, thetemperature of the exhaust gas 116 has been reduced to near ambienttemperatures. The near ambient temperature of the exhaust gas 116enables the turbo-compressor 124 to efficiently pump the exhaust gas 116back to atmospheric pressure or greater with a reduced work burden onthe turbo-expander 122. For example, the exhaust gas entering theturbo-compressor 124 may be within a temperature range of about 35-45degrees F. and may be within a pressure range of about 0.2 atmospheresor less, while the exhaust gas 116 exiting the turbo-compressor 124 maybe within a temperature range of about 55-65 degree F. and may have anatmospheric pressure of about 1.5 to 2 atmospheres.

By reducing the work burden of the turbo-compressor 124 on theturbo-expander 122, the net energy produced by the bottoming cyclegenerator 128 is increased significantly. Additionally, the componentsin the exhaust gas processing system 108 (such as the cooling towers144, 158, the cooling tower heat exchanger 136, the absorption chiller148, the absorption chiller heater exchanger 138 and the dehumidifiersystem 140) are selected to consume the least amount of operating powerand provide the least amount of exhaust gas pressure drop through theexhaust gas processing system. By doing so, the second electrical output118 power of the bottoming cycle generator 128 is maximized.

As such, the second electrical output 118 of the bottoming cyclegenerator 128 may be operable to provide a significant portion ofelectric power required to operate the exhaust gas processing system104. Additionally, the second electrical output 118 of the bottomingcycle generator 128 may be operable to provide all electric powerrequired to operate the exhaust gas processing system 104. Additionally,the second electrical output 118 of the bottoming cycle generator 128may be operable to provide a portion of electric power required tooperate the exhaust gas processing system 108 and the carbon dioxidecapture system 134. Additionally, the second electrical output 118 ofthe bottoming cycle generator 128 may be operable to provide allelectric power required to operate the exhaust gas processing system 104and the carbon dioxide capture system 134.

After the exhaust gas 116 exits the turbo-compressor 124, the exhaustgas 116 is routed through the carbon dioxide capture system 134. Forpurposes of clarity, the functional details of the carbon dioxidecapture system 134 will be discussed in greater detail with reference toFIG. 6.

From the carbon dioxide capture system 134, the exhaust gas 116 flowsthrough the second path 132 of the exhaust gas heat exchanger 106. Thecooled exhaust gas 116 passing through the second path 132 is reheatedby the hot exhaust gas 116 passing through the first path 130 of theexhaust gas heat exchanger 106. The reheated exhaust gas 116 exiting thesecond path 132 is significantly above ambient temperatures (forexample, 200 to 300 degrees F.) and is significantly less dense than theambient air. Accordingly, the reheated exhaust gas 116 may readily flowup the stack 164 of the combined power system 100.

Referring to FIG. 4, a schematic is depicted of an example of a moredetailed view of the absorption chiller heat exchanger 138 andassociated absorption chiller 148 that may be utilized in the exhaustgas processing system of FIG. 3, in accordance with the presentdisclosure.

The absorption chiller 148 has a generator section 166, a condensersection 168, an evaporator section 170 and an absorption section 172 allin fluid communication with each other and operable to circulate anabsorption chiller refrigerant 174 (in this example, water)therethrough. The generator section 166 has a generator section heatexchanger 176 to receive the flow of heated engine coolant fluid thatflows in the engine coolant loop 154 between the generator section heatexchanger 176 and the internal combustion engine 110. The generatorsection heat exchanger 176 is operable to evaporate the absorptionchiller refrigerant 174 to remove heat from the engine coolant fluid,which may enter the generator section heat exchanger at about 190degrees F.

More specifically in this example, the heat from the hot engine coolantevaporates the water-refrigerant 174 from a dilute brine solution ofwater and lithium bromide. The evaporated water 174 then flows to thecondenser section 168.

The condenser section 168 is operable to condense the absorption chillerrefrigerant 174 utilizing the water tower coolant loop 160 of the watertower 158. The condensed water 174 flows through an orifice 175 to dropits pressure as the water 174 enters the evaporator section 170.

The evaporator section 170 has an evaporator section heat exchanger 178to receive the absorption chiller coolant fluid from the absorptionchiller heat exchanger 138. The evaporator section heat exchanger 178 isoperable to remove heat from the absorption chiller coolant fluid byre-evaporating the water 174 condensed in the condenser section 168 toproduce steam (i.e., evaporated absorption chiller refrigerant) 174.

The steam then flows to the absorption section 172, which contains aconcentrated solution of brine that is operable to re-condense the water174 utilizing the water tower coolant loop 160 of the water tower 158.An absorption chiller refrigerant pump 180 pumps the concentrated brineback to the generator section 166 to complete the absorption chillerrefrigeration cycle.

Referring to FIG. 5, a schematic is depicted of an example of a moredetailed view of the cooling tower heat exchanger 136 and associatedcooling tower 144 that may be utilized in the exhaust gas processingsystem of FIG. 3, in accordance with the present disclosure. In thisspecific example, the cooling tower coolant fluid 141 that flows throughthe cooling tower coolant loop 142 is water. However, other coolingtower coolant fluids may also be used or included with the water, suchas, for example, glycol or the like.

During operation, a cooling tower coolant pump 182 may be used tocirculate the water (cooling tower coolant fluid) 141 through thecooling tower coolant loop 142 between the cooling tower heat exchangeand the water tower 144. The water 141 from the water tower 144 mayenter the exhaust gas heat exchanger 136 in a range of about 70 to 90degrees F. The exhaust gas 116 may enter the exhaust gas heat exchanger136 in a range of about 200-300 degrees F. The water 141 will cool theexhaust gas 116 as the water and exhaust gas pass through the coolingtower heat exchanger 136. For example, the exhaust gas 116 may be cooleddown to a range of about 100-130 degrees F. and the water may be heatedup to a temperature range of about 150-180 degrees F. as both the water141 and exhaust gas 116 pass through the cooling tower heat exchanger136.

After passing through the cooling tower heat exchanger 136, the heatedwater 141 will return to the upper portion 196 of the cooling tower 144where the water enters the cooling tower's coolant distribution system184. The distribution system 184 will route the water 141 through aplurality of cooling tower nozzles 186, which will spray the water ontoa fill material 188. The fill material (or fill media) 188 is a materialused to increase the surface area of the cooling tower 144. The fillmaterial 188 may be, for example, knitted metal wire, ceramic rings orother materials that provide a large surface area when positioned orpacked together within the cooling tower 144. The fill material 188slows the water 141 down and exposes a large amount of water surfacearea to air-water contact.

Ambient air 190 is pulled through a lower portion 198 of the coolingtower 144 and out the upper portion 196 of the cooling tower 144 via acooling tower fan 192. A small amount of water 141 evaporates as the air190 and water 141 contact each other in the fill material 188, whichcools the water. For example, the water 141 may be cooled down to arange of about 70 to 90 degrees F.

The cooled water 141 falls into a collection basin 194, which adds backmake-up water to compensate for the small amount of water that has beenevaporated during the evaporative cooling process. The cooled water 141is then pumped through the cooling tower coolant loop 142 and back tothe cooling tower heat exchanger 136 via the cooling tower coolant pump182 to complete the refrigeration cycle.

The cooling tower 144 may be one of several types of cooling towers,such as crossflow cooling towers, counterflow cooling towers, open loopcooling towers, closed loop cooling towers or the like. However, theymost often operate utilizing evaporative cooling produced from air tocooling tower coolant fluid (e.g., water) contact.

Referring to FIG. 6, a schematic is depicted of an example of anenlarged view of the carbon dioxide capture system 134 utilized in thecombined power system 100 of FIG. 3, in accordance with the presentdisclosure. As the exhaust gas 116 exits the turbo-compressor 124 itwill undesirably contain carbon dioxide 206. To remove the carbondioxide 206 prior to entering the exhaust gas heat exchanger 106, thecarbon dioxide capture system 136 may be utilized.

The carbon dioxide capture system 134 includes a first capture tank 200and a second capture tank 202. Each capture tank 200, 202 containscarbon dioxide absorbent material 204 operable to absorb carbon dioxide206 from the exhaust gas 116. The carbon dioxide absorbent material maybe zeolite, metal organic frameworks material, calcium hydroxide or thelike.

The first and second capture tanks 200, 202 each include an exhaust gasinlet port 208A and 208B, which are selectively connectable to the flowof exhaust gas 116 from the turbo-compressor 124. In other words, theexhaust gas inlet ports 208A and 208B are selectively connectable to theflow of exhaust gas prior to the exhaust gas passing through the carbondioxide absorbent material. More specifically, flow valve 210A controlsflow of exhaust gas 116 into the exhaust gas inlet port 208A of thefirst capture tank 200 and flow valve 210B controls flow of exhaust gas116 into the exhaust gas inlet port 208B of the second capture tank 202.

The first and second capture tanks 200, 202 also include an exhaust gasoutlet port 212A and 212B, which are selectively connectable to thesecond flow path 132 of the exhaust gas heat exchanger 106. In otherwords, the exhaust gas outlet ports 212A and 212B are selectivelyconnectable to the flow of exhaust gas after the flow of exhaust gas haspassed through carbon dioxide absorbent material. More specifically,flow valve 214A controls flow of exhaust gas 116 out of the exhaust gasoutlet port 212A of the first capture tank 200 and into the second flowpath 132 of the exhaust gas heat exchanger 106. Additionally, flow valve214B controls flow of exhaust gas 116 out of the exhaust gas outlet port212B of the second capture tank 202 and into the second flow path 132 ofthe exhaust gas heat exchanger 106.

The first and second capture tanks 200, 202 also include a carbondioxide outlet port 216A and 216B, which are selectively connectable toa carbon dioxide compressor 220. More specifically, flow valve 218Acontrols flow of regenerated carbon dioxide 206 out of the carbondioxide outlet port 216A of the first capture tank 200 and into thecarbon dioxide compressor 220. Additionally, flow valve 218B controlsflow of regenerated carbon dioxide 206 out of the carbon dioxide outletport 216B of the second capture tank 202 and into the carbon dioxidecompressor 220. The carbon dioxide compressor 220 is operable to pumpcarbon dioxide 206 out of the carbon dioxide outlet ports 216A, 216Bthat the carbon dioxide compressor 220 is connected to. The carbondioxide compressor 220 may be a rotary screw type compressor, a pistoncompressor or the like.

A compressor coolant loop 222 is selectively connectable between thecarbon dioxide compressor 220 and the first capture tank 200 or betweenthe carbon dioxide compressor 220 and the second capture tank 202. Thecompressor coolant loop 222 is operable to flow a compressor coolantfluid 224 (such as water, glycol of the like) to remove a heat ofcompression from the compressor 220 and to transfer the heat ofcompression to the first or second capture tanks 200, 202. The heat ofcompression is operable to release a portion of the carbon dioxide 206absorbed by the carbon dioxide absorbent material 204 in the first orsecond capture tanks 200, 202.

More specifically, the compressor coolant loop 222 includes a compressorcoolant jacket 226 of the compressor 220, a first capture tank heatingjacket 228 of the first capture tank 200 and a second capture tankheating jacket 230 of the second capture tank 202. The compressorcoolant jacket 226 is operable to contain and circulate the compressorcoolant fluid 224 around the outer surface of the compressor 220 to coolthe compressor 220. The compressor coolant fluid 224 will remove theheat of compression from the compressor 220.

For purposes herein, a heating or coolant jacket (such as coolant jacket226, and heating jackets 228 and 230) may refer to an outer casing orsystem of tubing, which holds fluid and through which the fluidcirculates to cool or heat a vessel or device. For example, thecompressor coolant jacket 226 may be a casing which surrounds the carbondioxide compressor 220 to enable the coolant fluid to absorb the heat ofcompression and to cool the compressor 220. Also, the first and secondcapture tank heating jackets 228 and 230 may be casings or systems oftubing, which are operable to transfer the heat of compression to theselected first or second capture tanks 200, 202 and to heat the carbondioxide 206 captured within the selected tank 200, 202.

The heating jackets 228 and 230 are operable to selectively contain andcirculate the compressor coolant fluid 224 (which is heated with theheat of compression from compressor 220) around the outer surfaces ofthe first or second capture tanks 200, 202 respectively to heat theselected capture tank 200, 202. The compressor coolant fluid 224 willadd the heat of compression to the selected capture tank 200, 202. Theheat of compression from the compressor 220 will then advantageously beused to regenerate (or desorb) a portion, or substantially all, of thecarbon dioxide 206 from the carbon dioxide absorbent material 204 sothat it can be pumped by the compressor 220 into a holding tank 232 forlater use and/or disposal.

A carbon dioxide heat exchanger 244 may be disposed between the holdingtank 232 and the carbon dioxide compressor 220 to cool the carbondioxide 206 prior to entering the holding tank 232. The carbon dioxideheat exchanger 244 may be cooled by a cooling tower 246 that circulatescoolant fluid between the cooling tower 246 and the carbon dioxide heatexchanger 244 via carbon dioxide heat exchanger coolant loop 248.

The compressor coolant fluid 224 is pumped around the compressor coolantloop 222 via pump 234. Flow valves 236, 238, 240 and 242 control theflow of compressor coolant fluid 224 to either the first capture tank200 or second capture tank 202. More specifically, when valves 236 and238 are open, and valves 240 and 242 are closed, the coolant loop 222circulates the coolant fluid 224 via pump 234 between the compressor 220and the first capture tank 200. In this configuration, the compressor220 is cooled and the first capture tank 200 is heated. When the valves236 and 238 are closed, and valves 240 and 242 are open, the coolantloop 222 circulates the coolant fluid 224 via pump 234 between thecompressor 220 and the second capture tank 202. In this configuration,the compressor 220 is cooled and the second capture tank 202 is heated.

During operation, the various flow valves may be configured such thatthe exhaust gas inlet port 208A of the first capture tank 200 isconnected (i.e., in fluid communication) to the flow of exhaust gas 116from the turbo-compressor 124. In other words, the exhaust gas inletport 208A is connected to the flow of exhaust gas 116 prior to theexhaust gas 116 passing through the carbon dioxide absorbent material204. Additionally, the first capture tank's exhaust gas outlet port 212Ais connected (i.e., in fluid communication) to the second flow path 132of the exhaust gas heat exchanger 106. In other words, the exhaust gasoutlet port 212A is connected to the flow of exhaust gas 116 after theexhaust gas has passed through the carbon dioxide absorbent material204. Additionally, the carbon dioxide compressor 220 may be connected tothe carbon dioxide outlet port 216B of the second capture tank 202 andthe compressor coolant loop 222 may be connected between the carbondioxide compressor 220 and the second capture tank 202. In thisconfiguration, exhaust gas 116 will flow into the first capture tank 200to remove the carbon dioxide 206 from the exhaust gas 116 flow prior toentering the exhaust gas heat exchanger 106. Simultaneously, the heat ofcompression from the carbon dioxide compressor 220 will advantageouslybe used to heat the second capture tank 202 to regenerate the carbondioxide from the second capture tank 202 and to pump the carbon dioxide206 into the holding tank 232. By using the heat of compression of thecarbon dioxide compressor 220 to regenerate the carbon dioxide in thesecond capture tank 202, the energy needed from external sources (suchas electric heaters or the like) to regenerate the carbon dioxide isadvantageously reduced.

Also during operation, the various flow valves may be configured suchthat the exhaust gas inlet port 208B of the second capture tank 202 isconnected (i.e., in fluid communication) to the flow of exhaust gas 116from the turbo-compressor 124. In other words, the exhaust gas inletport 208B is connected to the flow of exhaust gas 116 prior to theexhaust gas 116 passing through the carbon dioxide absorbent material204. Additionally, the second capture tank's exhaust gas outlet port212B is connected (i.e., in fluid communication) to the second flow path132 of the exhaust gas heat exchanger 106. In other words, exhaust gasoutlet port 212B is connected to the flow of exhaust gas 116 after theexhaust gas 116 has passed through the carbon dioxide absorbent material204. Additionally, the carbon dioxide compressor 220 may be connected tothe carbon dioxide outlet port 216A of the first capture tank 200 andthe compressor coolant loop 222 may be connected between the carbondioxide compressor 220 and the first capture tank 200. In thisconfiguration, exhaust gas will flow into the second capture tank 202 toremove the carbon dioxide 206 from the exhaust gas 116 flow prior toentering the exhaust gas heat exchanger 106. Simultaneously, the heat ofcompression from the carbon dioxide compressor 220 will advantageouslybe used to heat the first capture tank 200 to regenerate the carbondioxide from the first capture tank 200 and pump the carbon dioxide intothe holding tank 232. By using the heat of compression of the carbondioxide compressor 220 to regenerate the carbon dioxide in the firstcapture tank 200, the energy needed from external sources (such aselectric heaters or the like) to regenerate the carbon dioxide isadvantageously reduced.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail herein (providedsuch concepts are not mutually inconsistent) are contemplated as beingpart of the inventive subject matter disclosed herein. In particular,all combinations of claimed subject matter appearing at the end of thisdisclosure are contemplated as being part of the inventive subjectmatter disclosed herein.

Although the invention has been described by reference to specificexamples, it should be understood that numerous changes may be madewithin the spirit and scope of the inventive concepts described.Accordingly, it is intended that the disclosure not be limited to thedescribed examples, but that it have the full scope defined by thelanguage of the following claims.

What is claimed is:
 1. A bottoming cycle power system comprising: aturbine-generator comprising a turbo-expander and turbo-compressordisposed on a turbo-crankshaft, wherein: the turbo-expander operates torotate the turbo-crankshaft as a flow of exhaust gas from a combustionprocess passes through the turbo-expander, and the turbo-compressoroperates to compress the flow of exhaust gas after the exhaust gaspasses through the turbo-expander; an exhaust gas heat exchangercomprising a first flow path and a second flow path which operate toexchange heat therebetween, wherein: the first flow path operates toreceive the flow of exhaust gas from the turbo-expander prior to theexhaust gas being compressed by the turbo-compressor, and the secondflow path operates to receive the flow of exhaust gas from theturbo-compressor after the exhaust gas has been compressed by theturbo-compressor; and an exhaust gas processing system to receive andcool the flow of exhaust gas after the exhaust gas has passed throughthe first flow path of the exhaust gas heat exchanger and prior to theexhaust gas being compressed by the turbo-compressor, wherin; theexhaust gas processing system comprises at least one of a cooling tower,a cooling tower heat exchanger, and absorption chiller, an absorptionchiller heat exchanger, a dehumidifier system and a vapor-compressionrefrigeration system.
 2. The bottoming cycle power system of claim 1,wherein: the cooling tower heat exchanger of the exhaust gas processingsystem operates to receive the flow of exhaust gas from the exhaust gasheat exchanger and to cool the exhaust gas with a flow of cooling towercoolant fluid that flows in a cooling tower coolant loop between thecooling tower of the exhaust gas oricessubg system and the cooling towerheat exchanger of the exhaust gas processing system.
 3. The bottomingcycle power system of claim 2, wherein: the absorption chiller heatexchanger of the exhaust gas processing system operates to receive theflow of exhaust gas from the cooling tower heat exchanger and to coolthe exhaust gas with a flow of absorption chiller coolant fluid thatflows in an absorption chiller coolant loop between the absorptionchiller of the exhaust gas processing system and the absorption chillerheat exchanger of exhaust gas processing system.
 4. The bottoming cyclepower system of claim 3, comprising: the absorption chiller furthercomprising a generator section, a condenser section, an evaporatorsection and an absorption section all in fluid communication with eachother and which operate to circulate an absorption chiller refrigeranttherethrough, wherein: the generator section has a generator sectionheat exchanger to receive a flow of engine coolant fluid that flows inan engine coolant loop between the generator section heat exchanger andan internal combustion engine, the internal combustion engine generatingthe flow of exhaust gas, the generator section heat exchanger operatesto evaporate the absorption chiller refrigerant to remove heat from theengine coolant fluid; the condenser section operates to condense theabsorption chiller refrigerant; the evaporator section has an evaporatorsection heat exchanger to receive the absorption chiller coolant fluidfrom the absorption chiller heat exchanger, the evaporator section heatexchanger operates to remove heat from the absorption chiller coolantfluid by re-evaporating the absorption chiller refrigerant; and theabsorption section operates to re-condense the absorption chillerrefrigerant.
 5. The bottoming cycle power system of claim 1, wherein:the absorption chiller heat exchanger of the exhaust gas processingsystem operates to receive the flow of exhaust gas from the exhaust gasheat exchanger and to cool the exhaust gas with a flow of absorptionchiller coolant fluid that flows in an absorption chiller coolant loopbetween the absorption chiller of the exhaust gas processing system andthe absorption chiller heat exchanger of the exhaust gas processingsystem.
 6. The bottoming cycle power system of claim 1 comprising acarbon dioxide capture system, the carbon dioxide capture systemcomprising: a first capture tank and a second capture tank, each of thefirst capture tank and the second capture tank containing carbon dioxideabsorbent material which operates to absorb carbon dioxide from theexhaust gas, the first capture tank and the second capture tank eachcomprising: an exhaust gas inlet port connected to the flow of exhaustgas from the turbo-compressor, an exhaust gas outlet port connected tothe second flow path of the exhaust gas heat exchanger, and a carbondioxide outlet port; a carbon dioxide compressor, connected to thecarbon dioxide outlet port of either the first capture tank or thesecond capture tank, the carbon dioxide compressor operates to pumpcarbon dioxide out of the carbon dioxide outlet port that the carbondioxide compressor is connected to; and a compressor coolant loopconnected between the carbon dioxide compressor and the first capturetank or between the carbon dioxide compressor and the second capturetank, the compressor coolant loop operates to flow a compressor coolantfluid to remove heat of compression from the compressor and to transferthe heat of compression to the first capture tank or the second capturetank, wherein the heat of compression operates to release a portion ofthe carbon dioxide absorbed by the carbon dioxide absorbent material inthe first capture tank or the second capture tank.
 7. The bottomingcycle power system of claim 6, wherein: when the exhaust gas inlet portof the first capture tank is connected to receive the flow of exhaustgas from the turbo-compressor, then the exhaust gas outlet port of thefirst capture tank is connected to output the flow of exhaust gas to thesecond flow path of the exhaust gas heat exchanger, the carbon dioxidecompressor is connected to the carbon dioxide outlet port of the secondcapture tank and the compressor coolant loop is connected between thecarbon dioxide compressor and the second capture tank; and when theexhaust gas inlet port of the second capture tank is connected torecieve the flow of exhaust gas from the turbo-compressor, then theexhaust gas outlet port of the second capture tank is connected tooutput the flow of exhaust gas to the second flow path of the exhaustgas heat exchanger, the carbon dioxide compressor is connected to thecarbon dioxide outlet port of the first capture tank and the compressorcoolant loop is connected between the carbon dioxide compressor and thefirst capture tank.
 8. The bottoming cycle power system of claim 6,wherein the turbine-generator comprises: a bottoming cycle generatordisposed on the turbo-crankshaft, the bottoming cycle generatorconnected to the exhaust gas processing system and the carbon dioxidecapture system, the bottoming cycle generator operates to provide aportion of electric power required to operate the exhaust gas processingsystem and the carbon dioxide capture system.
 9. The bottoming cyclepower system of claim 8, wherein the bottoming cycle generator operatesto provide all electric power required to operate the exhaust gasprocessing system and the carbon dioxide capture system.
 10. Thebottoming cycle power system of claim 1, wherein the turbine-generatorcomprises: a bottoming cycle generator disposed on the turbo-crankshaft,the bottoming cycle generator connected to the exhaust gas processingsystem operates to provide a portion of electric power required tooperate the exhaust gas processing system.
 11. The bottoming cycle powersystem of claim 10, wherein the bottoming cycle generator operates toprovide all electric power required to operate the exhaust gasprocessing system.
 12. A combined power system comprising: a primarypower system including an internal combustion engine having a rotatablecrankshaft, the engine operating to combust fuel in a combustion processto deliver primary power to the engine crankshaft, the combustionprocess producing a flow of exhaust gas; and a bottoming cycle powersystem comprising: a turbine-generator comprising a turbo-expander andturbo-compressor disposed on a turbo-crankshaft, wherein: theturbo-expander operates to rotate the turbo-crankshaft as the flow ofexhaust gas from the combustion process passes through theturbo-expander, and the turbo-compressor operates to compress the flowof exhaust gas after the exhaust gas passes through the turbo-expander,an exhaust gas heat exchanger comprising a first flow path and a secondflow path which operate to exchange heat therebetween, wherein: thefirst flow path operates to receive the flow of exhaust gas from theturbo-expander prior to the exhaust gas being compressed by theturbo-compressor, and the second flow path operates to receive the flowof exhaust gas from the turbo-compressor after the exhaust gas has beencompressed by the turbo-compressor, and an exhaust gas processing systemto receive and cool the flow of exhaust gas after the exhaust gas haspassed through the first flow path of the exhaust gas heat exchanger andprior to the exhaust gas being compressed by the turbo-compressor,wherin: the exhaust gas processing system comprises at least one of acooling tower, a cooling tower heat exchanger, and absorption chiller,and absorption chiller heat exchanger, a dehumidifier system and avapor-compression refrigeration system.
 13. The combined power system ofclaim 12, wherein the exhaust gas processing system comprises: thecooling tower heat exchanger which operates to receive the flow ofexhaust gas from the exhaust gas heat exchanger and to cool the exhaustgas with a flow of cooling tower coolant fluid that flows in a coolingtower coolant loop between a cooling tower and the cooling tower heatexchanger.
 14. The combined power system of claim 12, wherein theexhaust gas processing system comprises: the absorption chiller heatexchanger of the exhaust gas processing system operates to receive theflow of exhaust gas from the exhaust gas heat exchanger and to cool theexhaust gas with a flow of absorption chiller coolant fluid that flowsin an absorption chiller coolant loop between the absorption chiller ofthe exhaust gas processing system and the absorption chiller heatexchanger of the exhaust gas processing system.
 15. The combined powersystem of claim 14, comprising: the absorption chiller furthercomprising a generator section, a condenser section, an evaporatorsection and an absorption section all in fluid communication with eachother and which operate to circulate an absorption chiller refrigeranttherethrough, wherein: the generator section has a generator sectionheat exchanger to receive a flow of engine coolant fluid that flows inan engine coolant loop between the generator section heat exchanger andthe internal combustion engine of the primary power system, thegenerator section heat exchanger operates to evaporate the absorptionchiller refrigerant to remove heat from the engine coolant fluid; thecondenser section operates to condense the absorption chillerrefrigerant; the evaporator section has an evaporator section heatexchanger to receive the absorption chiller coolant fluid from theabsorption chiller heat exchanger, the evaporator section heat exchangeroperates to remove heat from the absorption chiller coolant fluid byre-evaporating the absorption chiller refrigerant; and the absorptionsection operates to re-condense the absorption chiller refrigerant. 16.The combined power system of claim 12 comprising a carbon dioxidecapture system, the carbon dioxide capture system comprising: a firstcapture tank and a second capture tank, each of the first capture tankand the second capture tank containing carbon dioxide absorbent materialwhich operates to absorb carbon dioxide from the exhaust gas, the firstcapture tank and the second capture tank each comprising: an exhaust gasinlet port connected to the flow of exhaust gas from theturbo-compressor, an exhaust gas outlet port connected to the secondflow path of the exhaust gas heat exchanger, and a carbon dioxide outletport; a carbon dioxide compressor connected to the carbon dioxide outletport of either the first capture tank or the second capture tank, thecarbon dioxide compressor operates to pump carbon dioxide out of thecarbon dioxide outlet port that the carbon dioxide compressor isconnected to; and a compressor coolant loop connected between the carbondioxide compressor and the first capture tank or between the carbondioxide compressor and the second capture tank, the compressor coolantloop operates to flow a compressor coolant fluid to remove heat ofcompression from the compressor and to transfer the heat of compressionto the first capture tank or the second capture tank, wherein the heatof compression operates to release a portion of the carbon dioxideabsorbed by the carbon dioxide absorbent material in the first capturetank or the second capture tank.
 17. The combined power system of claim16, wherein the turbine-generator comprises: a bottoming cycle generatordisposed on the turbo-crankshaft, the bottoming cycle generatorconnected to the exhaust gas processing system and the carbon dioxidecapture system, the bottoming cycle generator operates to provide allelectric power required to operate the exhaust gas processing system andthe carbon dioxide capture system.
 18. The combined power system ofclaim 12, wherein the turbine-generator comprises: a bottoming cyclegenerator disposed on the turbo-crankshaft, the bottoming cyclegenerator connected to the exhaust gas processing system and operates toprovide all electric power required to operate the exhaust gasprocessing system.
 19. A carbon dioxide capture system comprising: afirst capture tank and a second capture tank, each of the first capturetank and the second capture tank containing carbon dioxide absorbentmaterial which operates to absorb carbon dioxide from a flow of exhaustgas, the first capture tank and the second capture tank each comprising:an exhaust gas inlet port being connected to the flow of exhaust gasprior to the exhaust gas passing through the carbon dioxide absorbentmaterial, an exhaust gas outlet port being connected to the flow ofexhaust gas after the flow of exhaust gas has passed through carbondioxide absorbent material, and a carbon dioxide outlet port; a carbondioxide compressor connected to the carbon dioxide outlet port of eitherthe first capture tank or the second capture tank, the carbon dioxidecompressor operating to pump carbon dioxide out of the carbon dioxideoutlet port that the carbon dioxide compressor is connected to; and acompressor coolant loop connected between the carbon dioxide compressorand the first capture tank or between the carbon dioxide compressor andthe second capture tank, the compressor coolant loop operating to flow acompressor coolant fluid to remove heat of compression from thecompressor and to transfer the heat of compression to the first capturetank or the second capture tank, wherein the heat of compressionoperates to release a portion of the carbon dioxide absorbed by thecarbon dioxide absorbent material in the first capture tank or thesecond capture tank.
 20. The carbon dioxide capture system of claim 19,wherein: when the exhaust gas inlet port of the first capture tank isconnected to receive the flow of exhaust gas prior to the exhaust gaspassing through the carbon dioxide absorbent material, then the exhaustgas outlet port of the first capture tank is connected to output theflow of exhaust gas after the exhaust gas has passed through the carbondioxide absorbent material, the carbon dioxide compressor is connectedto the carbon dioxide outlet port of the second capture tank and thecompressor coolant loop is connected between the carbon dioxidecompressor and the second capture tank; and when the exhaust gas inletport of the second capture tank is connected to receive the flow ofexhaust gas prior to the exhaust gas passing through the carbon dioxideabsorbent material, then the exhaust gas outlet port of the secondcapture tank is connected to output the flow of exhaust gas after theexhaust gas has passed through the carbon dioxide absorbent material,the carbon dioxide compressor is connected to the carbon dioxide outletport of the first capture tank and the compressor coolant loop isconnected between the carbon dioxide compressor and the first capturetank.